A method of manufacturing a solid-rolled railway wheels

 

(57) Abstract:

The invention relates to metallurgy, in particular to the technology of solid-rolled railway wheels. The technical result of the invention is the provision of properties in the disk and the wheel rim when surfacing with the rolling heat at the level corresponding to the heat with separate heating. The technical result is achieved due to optimization of the end temperature of deformation and temperature quenching of the wheel, namely the temperature of the end of the plastic deformation of the support in the interval 960-880°C, and the temperature of the wheel before hardening in the interval 940-780°C, and the duration poslerevolutsionnoi pause before hardening is not more than 150 C. for 1 h.p. f-crystals, 2 tab.

The invention relates to metallurgy, in particular, to a technology of solid-rolled railway wheels.

A known method of manufacture of railway wheels, comprising heating the billet to a temperature of 1270oC, continuous deformation by the press wheel and the mill with the end of the deformation at a temperature of 1050 - 1100oC, isothermal aging at a temperature of 650oC, heat treatment with the STV wheels however, is long-lasting and energy-intensive.

Closest to the present invention is a method of manufacture of railway wheels, comprising heating the workpiece under deformation to a temperature of 1270oC, the deformation of the presses and the mill with the end of the deformation at a temperature of 1050 - 1100oC, the hardening of the wheel rim after deformation and his leave.

The disadvantage of this method is low plastic characteristics of the metal rim and unstable impact strength of the wheel due to the poor structure formed at high temperature end of deformation (the size of the actual grain is 2-4 points).

The objective of the invention is to develop a method of manufacture of railway wheels, providing properties in the disk and the wheel rim when surfacing with the rolling heat at the level corresponding to the heat with separate heating.

The technical result in achieving the properties of the metal of the rim and disk-level heat with separate heating is achieved by optimizing end temperature deformation and temperature quenching of the wheel, namely the temperature akonaditray 940 - 780oC, and the duration poslerevolutsionnoi pause before hardening is not more than 150 C.

The invention consists in the following.

In the temperature range of end deformation 960 - 880oC and subsequent hardening rolling heating 940 - 780oC structure is formed in the disk and the wheel rim, providing a level properties of these elements in accordance with the requirements of GOST 10791. The size of the actual grain in the disk and the rim in the proposed temperature range the end of the deformation and before hardening, respectively and 4-6 6-8 points.

Different grain size in the disk and the wheel rim due, in particular, endured varying degrees of deformation and conditions poslerevolyutsionnogo cooling of these elements of the wheel. So, in the rim and the wheel disc maximum altitude deformation, respectively 60 and 90%, and the speed poslerevolyutsionnogo cooling wheel disc greatly exceeds the rate of cooling of the massive rim that defines the different velocity recrystallization in these elements of the wheel.

The proposed temperature range the end of the deformation depending on the content of coal is round the end of the deformation at specified intervals and depending on the carbon content averaged structure and mechanical properties of the metal disk and the rim. Thus, the higher temperature end of the deformation for the bottoms with low carbon content (0,53 - 0,57%) can reduce the number of structurally free ferrite and the distance between pearlite colonies in the perlite, which improves tensile strength of the metal at high resource ductility and toughness provide low carbon content. At high carbon content (0,63 - 0,67%) lowering the temperature of the end of the deformation increases resource of plasticity and toughness, which is achieved by increasing the number of structurally free ferrite and of distance between pearlite colonies in perlite, and additional grind the actual grain.

The cumulative impact of these structural factors allows to obtain the mechanical properties of the rim and disc in accordance with the requirements of GOST 10791.

The temperature range of the wheel before hardening rolling heating is 940 - 780oC and depending on the carbon content and is within:

C, % -oC

0,53 - 0,57 - 940 - 840

0,58 - 0,62 - 910 - 810

0,63 - 0,67 - 880 - 780

Temperature limits before hardening in each of the 3 groups on the carbon content aboslutely according to the proposed method is not more than 150 C.

So, after transportation of the wheel to tempering machine maximum temperature before hardening for each of the 3 groups on carbon, respectively 940, 910 880oC. the Maximum temperature before hardening of the wheel in accordance with the maximum duration poslerevolutsionnoi pause 150, according to the proposed method, for each of the 3 groups on carbon, respectively 840, 810, 780oC.

Limit the duration poslerevolutsionnoi pause equal to 150 s, attributable to the following: with increasing duration poslerevolutsionnoi pause over 150 with reduced values of the plastic characteristics of the wheel rim, which is associated with the processes of recrystallization and growth of austenite grains and as a consequence increase the size of the pearlite colonies.

An example implementation of the method.

For industrial sampling method were selected three groups of blanks with carbon content, respectively, or 0.57, 0.62 to 0.67%. Manganese concentration was almost the same and amounted to 0.75 of 0.77%. After heating to a temperature of 1240oC blanks were predeterminately on units forging-rolling line, including the following technologically advanced, and the temperature value of the end of the deformation and temperature before hardening of the wheel, and also the vacation mode in accordance with the proposed method and technology of the prototype are shown in table 1.

The test results of the wheels, made by the proposed method and in accordance with the prototype are shown in table 2.

As shown, the regulation of the temperature of the end of the deformation and the temperature of the wheel before hardening allow us to greatly increase the level values of the plastic characteristics and toughness.

1. A method of manufacturing a solid-rolled railway wheels, comprising heating the workpiece to 1200 - 1240oWith the strain containing the precipitate, forming, rolling and vyybkw wheel, intermittent quenching and tempering, characterized in that the temperature of the end deformation of the support in the range of 960 - 880oTo carry out Polideportivo a pause with a duration of no more than 150 to the temperature of the wheel before quenching in the range 940 - 780oC.

2. The method according to p. 1, characterized in that the intermittent quenching is carried out at a vertical location of the wheel.

 

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